Refrigerator



Oct. 5, 1937.

T. l. POTTER REFRIGERATOR Filed Feb. 14, 1934 -k-Z 'l5 34 55 l, i .30 o26 35 3.0 5f, Z6? l 5 iirlz Z4 L ff Il ai 2 Sheets-Sheet l mvEN-roRTHOMAS I. Pon-ER BY W ATTORNEY T. l. POTTER REFRIGERATOR Filed Feb. 14.1934 Oct.v 5, 1937.-

2 Sheets-Sheet 2 INVENTR A THOMAS I. POTTER .w mow """Nmmmf PatentedOct. 5, 1937 y UNITEo STATE s PATENT oFFlcE nErmGERA'ron Thomas I.Potter, Buffalo, N. Y.

ipplication February 14, 1934, Serial No. 711,157 Y (o1.` ca -11s) l 1Claim.

in my copending application Serial No. 711,156,

led February 14, 1934, comprising a main cool' ing chamber having arelatively moist non-freezing atmosphere and an inner chamber Within thecooling chamberV in' which a temperature well below the freezing pointis maintained, with thermal impedance separating the two chambers. I usethe term thermal impedance" to distinguish from thermal insulation whichis commonly used to designate a material offering. a high resistance tothe passage of heat. The thermal impedance separating the chamberspermits heat to ow therethrough comparatively readily, but at the sametime it retards the heat flow to such 'an extent that although the innerchamber may be cooled far below the freezing point substantially nofrost will form in the outer chamber to rob'the same of moisture.

In the refrigerator described in said opend\ ing application the thermalimpedance is embodied in the walls of a casing enclosing one or moreinner chambers, said walls being preferably of metal with impedancematerial applied thereon as a coating. An object of the presentinventiony is to provide a structure in which a dead air space isemployed to impede the ow of heat from the outer chamber into the innerchambers.

In the refrigerator disclosed in said copending application there is anevaporator located in the interior of the casing, this evaporatorconstituting eitherl the sole or the principal cooling element of theouter and inner chambers so that separated therefrom by a thick wall I3of insu- Figure 1 is a view in vertical' seche through a refrigeratorembodying the present invention, the section being taken on line I--I ofFig. 2, and the casing and shroud being shown in side elevation andpartly brokenaway;

Fig. 2 is a fragmental view in section taken on the line 2-2 of Fig. land showing the casing Vwith associated parts in rear elevation;

' Fig. 3 is a fragmental view in section taken on line 3-3 of Fig. 4 andis similar to Fig. 1 but shows another embodiment of the invention inwhich an auxiliary non-frostingcoil is provided above the shroud in thecooling chamber;

Fig. 4 is a fragmental View in section taken on the line 4--4 of Fig. 3;and

- Fig. 5 is a view similar to Fig. 4 of still another embodiment inwhich the auxiliary coil is located at one side'of the shroud.

The refrigerator shown in Figs. lnd 2 is of the self-contained typeadapted for domestic use. It comprises a cabinet I0 having a lowerchamber II in which is located the usual heat pumping mechanism,generally indicated by the reference numeral I2. Above the chamber IIand lation is a main cooling chamber Il. This chamber is protected fromambient heat by the usual heat from the outer chamber must wholly or toa -large extent pass through the inner chambers to reach the evaporator.An object of the present inventionfis to provide a structure in whichthe evaporator is formed in or on the walls of the inner chambersinstead of being enclosed insulation walls I5 and a door. I6 ofinsulation material.

Suspended vwithinthe chamber I4 is a casing indicated generally by thereference numeral' I1 within which are two inner chambers I8 and I9disposed one above the other. 'I'he casing I1 is preferably made of twometallic shells 20 and 2| respectively, which are connected by straps22. An evaporator 23 is xed to the casing, being preferably formed oftwo layers of coils. One layer is located under the lower shell 2l,while the other is fitted between the shells 20 and 2l: In order tosecure the greatest possible leat conductivityv the evaporator coils arepreferably soldered, welded or otherwise integrally connected to theshells 20 and 2l. Refrigerant is pumped from thqheat pumping unit I2through a high pressure line 24 and thence through an expansion' 45valve 25 into 'the lower layer of coils-of the.^ evaporator and theexpanded refrigerant is drawn from the upper layer through a return line26 passing down to the unit I2.

Covering the casing I1, but spaced therefrom, 50 is a shroud 28 which isof inverted U-shape in vertical section so that it covers the top andthe sides of the casing I1. The shroud has a rear wall 29 which extendsdownwardly to blankotthe upper shell 2l part of the'lower 55 185 in theusual manner, is connected by a suitable shell 2|. If desired, thisshroud could be carried all the way down to cover the entire rear of thecasing. 'Ihe shroud is secured to the straps 22, and hangers 3 9depending from the top wall of the chamber Il are attached to theshroud,

d thereby suspending both shroud and casingwithinthe cooling chamber.

The casing is provided with a front wall 3| which extends up to theceiling ofthe chamber Il and which is formed with a doorway opening intothe inner chambers I3 and I9. .This doorway is normally closed by a door32. Mounted on the plate 3|, with an operating handle 33 projectingtherethrough is a thermostatic switch 34 having la heat sensitive bulb35 preferably attached to the shroud, although, if desired, it can beattached to the suction line 23. v

It will be observed that in this construction the evaporator 23constitutes the sole cooling element to catch any condensed moisture ofthe refrigerator. However, the evaporator is separated from the coolingchamber Il by the air space between the shroudr 28 and the casing I1.

Since there is practically no circulation ofair in this space the airlayer constitutes an impedance to the passage of heat. lSuspended belowthe casing I1'is a drip pan 33 which lies fairly close to the lowerlayer 'of coils of the evaporator 23. and the intervening air space alsoserves as thermal impedance at the un r side of the casing I1. This drippan is wide en h and long enough I dripping from the shroud 23.

In operation the inner chambers I3 and. I9 will -be much cooler thanthechamber It because of their direct metallic contact with' theevaporator chambers I8 and I9 will 'be far below .the freezing l l'point;

- series in the refrigerantline 24-23.

'7o the non-frosting coil ll is located above theY Because of theintervening layer of dead air no frost will form' on the exteriorsurface of the shroud. In fact, I nd in practice that little, if any,frost forms even on the outer surface of the walls f the shells 20 and2| because although the temperature oi' said walls may drop well belowthe freezing point there are no currents of air brushing over saidsurfaces to carry moisture thereto. As a result the atmosphere inchamber I4 is not robbed of its moisture by the formation of frost andconsequently it retains sufficient moisture to prevent foods from dryingout.

'Ihe construction shown in Figs. 3 and 4 differs from that shown inFigs. 1 and 2 mainly-'in the fact that an auxiliary coil 4I is used inthe cooling chamber u.- 'rms auxiliary coil whieli. is or thenon-frosting type. being provided with fins coupling Il to the lowpressure end of the'main coll 23 so that the two coils are connected inPreferably,

shroud 23 so that any moisture dripping therefrom will flow vdown Vtheshroud into the drip pan.

The coil 4I is supported on a U-shaped bracket 42 far enough above theshroud to prevent chillin g thelatterbelow the freezing point.

lamistoso The casing I1 is preferably located near one of the side wallsof the cooling chamber, as shown, and at the opposite side there is abaule plate M which conceals the finned coil as well as the shroud. Thisbame plate is mounted in spaced relation to the shroud 23, as clearlyshown in Fig. 4, and is formed with louvres 45 therethrough for thecirculationof air currents. I

The bulb 35 of the thermostatic switch 34 is clamped to the coil II ator near the low pressure end thereof, so that the operation ot. the heatpumping unit is controlled by the temperature oi' the coil at the pointof attachment at the bulb thereto. It will be understood, of course,that this will give control of temperature conditions in all of thechambers Il, I3 and I9 and that the inner chambers I 3 and I 9 will becooled first, the finned coil lil receiving only such liquefiedrefrigerant as has not already been boiled away in the coil 23. 'I'hechamber I4 will be cooled by the main coil as well as its non-frostingextension 4I, because heat from chamber Il will flow through the jacketof dead air surrounding the casing. I1. If desired, the shroud. not onlyin the structure lshown in Figs. l and 2 but also in that shown in Figs.3 and 4, may be enameled to further impede the pe of heat therethrough.Preferably the baille M -is enameled for sanitary purposes as well asappearance.

While it is desirable to have the auxiliary nonfrosting coil disposedabove the shroud, it will be obvious that it can be placed in anysuitable position in the chamber Il. For instance, in Fig. 5,

the finned coil 4I is shown as located between the shroud and theadjacent side wall of chamber I4.

As in the structures disclosed in said copend- The upper chamber I5 hasless exposed wall surface and consequently will be colder thanthe .ingapplication, it is pomble to obtain wide vari- 'l ations oftemperaturein the several chambers.

chamber ls, and both or these chambers wm bel spect to the auxiliarycoil 4I is controlled bythe setting of the expansion valve 25, but, inaddition to this control of relative temperatures the thermostaticswitch lis also controllable by the operation of the handle 33 in theusual way to determine at what temperatures the heat pumping unit wouldbe started and stopped.

While I have described several embodiments of my invention I wish it tobe understood that these are to be taken as illustrative and notlimitative and that I reserve the right to make such changes in form,construction and arrangement of parts as may fall within lthe spirit andscope of the following claim.

I claim:

A refrigerator comprising 'a cabinet formed i with a thermally insulatedcasing within the chamber providing an auxiliary main food chamber, a

food chamber, a shroud covering the casing and 65 sharp freezingtemperature while cooling the main chamber to a refrigeratingtemperature above the freezing point of water, said means comprising anevaporator in the auxiliary chamberand an extension thereof above theshroud i and in spaced relation thereto.' said extension exteriorthereof, means for controlling the opera.-

' tion of the refrigerating system to prevent coo!- ing the Aexternalsurface of the shroud and 'that of the extension below the frostingpoint, and s bsmeverticaliy disposed at one side of said extension andsaid shroud and spaced therefrom to direct convection currents from saidextension down the side of the shroud.

THOM'AS I.

